Certain 2-benzoyl-5-hydroxy-4,4,6,6-tetra-substituted-1,3-cyclohexanediones

ABSTRACT

Compounds of the formula ##STR1## wherein R is hydrogen; halogen; C 1  -C 2  alkyl; C 1  -C 2  alkoxy; nitro; cyano; C 1  -C 2  haloalkyl; or R a  SO n  -- wherein n is 0 or 2 and R a  is C 1  -C 2  alkyl, trifluoromethyl or difluoromethyl; or trifluoromethoxy or difluoromethoxy; 
     R 1  is hydrogen or C 1  -C 4  alkyl; 
     R 2  is hydrogen or C 1  -C 4  alkyl; or 
     R 1  and R 2  together are C 2  -C 5  alkylene; 
     R 3  is C 1  -C 4  alkyl; 
     R 4  is C 1  -C 4  alkyl; or 
     R 3  and R 4  together are C 2  -C 5  alkylene; 
     R 5  and R 6  independently are (1) hydrogen; (2) halogen; (3) C 1  -C 4  alkyl; (4) C 1  -C 4  alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C 1  -C 4  haloalkyl; (9) R b  SO n  -- wherein n is the integer 0, 1 or 2; and R b  is (a) C 1  -C 4  alkyl; (b) C 1  -C 4  alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR c  R d  wherein R c  and R d  independently are 2 hydrogen or C 1  -C 4  alkyl; (11) R e  C(O)-- wherein R e  is C 1  -C 4  alkyl or C 1  -C 4  alkoxy; or (12) --SO 2  NR c  R d  wherein R c  and R d  are as defined; and (13) --N(R c )C(O)R d  wherein R c  and R d  are as defined; and 
     R 7  is hydrogen, C 1  -C 4  alkyl, C 2  -C 5  alkenyl, C 2  -C 5  alkynyl or cyano, and their salts.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,202,890 relates to certain 1-hydroxy-2-(alkylketo)-4,4,6,6-tetramethylcyclohexene-3,5-diones as herbicides. The compounds have the following structural formula ##STR2## wherein R is alkyl.

DESCRIPTION OF THE INVENTION

This invention relates to 2-benzoyl-5-hydroxy-4,4,6,6-tetrasubstituted-1,3-cyclohexanediones and their use as herbicides.

Also embodied within the scope of this invention are novel compounds having the following structural formula ##STR3## wherein R is hydrogen; halogen; C₁ -C₂ alkyl, preferably methyl; C₁ -C₂ alkoxy, preferably methoxy; nitro; cyano; C₁ -C₂ haloalkyl, preferably trifluoromethyl; R^(a) SO_(n) -- wherein n is 0 or 2, preferably 2 and R^(a) is C₁ -C₂ alkyl, preferably methyl, trifluoromethyl or difluoromethyl; or trifluoromethoxy or difluoromethoxy. Preferably, R is chlorine, bromine, C₁ -C₂ alkyl, C₁ -C₂ alkoxy, trifluoromethyl, cyano, nitro, C₁ -C₂ alkylthio or C₁ -C₂ alkylsulfonyl; more preferably chlorine, nitro, methyl, trifluoromethyl or methylsulfonyl; and

R¹ is hydrogen or C₁ -C₄ alkyl, preferably methyl;

R² is hydrogen or C₁ -C₄ alkyl, preferably methyl; or

R¹ and R² together are C₂ -C₅ alkylene;

R³ is C₁ -C₄ alkyl, preferably methyl;

R⁴ is C₁ -C₄ alkyl, preferably methyl; or

R³ and R⁴ together are C₂ -C₅ alkylene;

R⁵ and R⁶ independently are (1) hydrogen; (2) halogen, preferably chlorine, fluorine or bromine; (3) C₁ -C₄ alkyl, preferably methyl; (4) C₁ -C₄ alkoxy, preferably methoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl, more preferably trifluoromethyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2, preferably 2; and

R^(b) is

(a) C₁ -C₄ alkyl, preferably methyl;

(b) C₁ -C₄ alkyl substituted with halogen or cyano, preferably chloromethyl, trifluoromethyl or cyanomethyl;

(c) phenyl; or

(d) benzyl;

(10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13) --N(R^(c))C(O)R^(d) wherein R^(e) and R^(d) are as defined; and R⁷ is hydrogen, C₁ -C₄ alkyl, C₂ -C₅ alkenyl, C₂ -C₅ alkynyl or cyano, preferably hydrogen.

Preferably R⁵ is in the 3-position or 5-position. More preferably R⁵ is hydrogen, chlorine, fluorine, trifluoromethyl, cyano, C₁ -C₄ alkoxy, C₁ -C₄ alkyl or C₁ -C₄ thioalkyl. Preferably R⁶ is in the 4-position. Most preferably R⁶ is halogen, cyano, trifluoromethyl, or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl, preferably methyl or C₁ -C₄ haloalkyl, preferably chloromethyl, difluoromethyl or trifluoromethyl.

The term "C₁ -C₄ alkyl" includes methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and t-butyl. The term "halogen" includes chlorine, bromine, iodine and fluorine. The terms "C₁ -C₄ alkoxy" includes methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, iso-butoxy and t-butoxy. The term "C₁ -C₄ haloalkyl" includes the alkyl groups defined above under C₁ -C₄ alkyl in which one or more hydrogens is replaced by chlorine, bromine, iodine or fluorine.

Salts of the above-described compounds (as defined hereinafter) are included within the scope of the instant invention.

The compounds of this invention can have the following four structural formulae because of tautomerism: ##STR4## wherein R, R¹, R², R³, R⁴, R⁵, R⁶ and R⁷ are as defined above.

The circled proton on each of the four tautomers is reasonably labile. These protons are acidic and can be removed by reaction with a base to form a salt having an anion of the following four resonance forms: ##STR5## wherein R, R¹, R², R³, R⁴, R⁵, R⁶ and R⁷ are as defined above.

Examples of cations of these bases are inorganic cations such as alkali metals, e.g. lithium, sodium and potassium; the alkaline earth metals, e.g. calcium and magnesium or ammonium or organic cations such as substituted ammonium, sulfonium, sulfoxonium or phosphonium wherein the substitutents are aliphatic or aromatic groups.

Those skilled in the art will recognize in considering the salts of this invention that varying degrees of association between the anion and cation will exist depending upon the nature of the cation. In some instances with a suitable cation, such as copper, the salt can exist in a chelated form.

The compounds of this invention and their salts are active herbicides of a general type. That is, they are herbicidally effective against a wide range of plant species. The method of controlling undesirable vegetation of the present invention comprises applying an herbicidally effective amount of the above-described compounds or their salts to the area where control is desired.

The compounds of the present invention can be prepared by the following two-step general method.

The process proceeds via the production of an enol ester intermediate as shown in reaction (1). The final product is obtained by rearrangement of the enol ester as shown in reaction (2). The two reactions may be conducted as separate steps by isolation and recovery of the enol ester using conventional techniques prior to conducting step (2), or by addition of a cyanide source to the reaction medium after the formation of the enol ester, or in one step by inclusion of the cyanide source at the start of reaction (1). ##STR6## wherein R through R⁷ and moderate base are as defined and X is halogen, preferably chlorine, C₁ -C₄ alkyl--C(O)--O--, C₁ -C₄ alkoxy--C(O)--O-- or ##STR7## wherein R, R⁵ and R⁶ in this portion of the molecule are identical with those in the reactant shown above and the moderate base is as defined, preferably tri-C₁ -C₆ alkylamine, alkali metal carbonate or alkali metal phosphate.

Generally, in step (1) mole amounts of the trione and substituted benzoyl reactant are used, along with a mole amount or excess of the base. The two reactants are combined in an organic solvent such as methylene chloride, toluene, ethyl acetate or dimethylformamide. The base or benzoyl reactant preferably is added to the reaction mixture with cooling. The mixture is stirred at 0° C.-50° C. until the reaction is substantially complete. ##STR8## wherein the moderate base and R through R⁷ are as defined above.

Generally, in step (2) a mole of the enol ester intermediate is reacted with 1 to 4 moles of the moderate base, preferably about 2 moles of moderate base and from 0.01 mole to about 0.5 mole or higher, preferably about 0.1 mole of the cyanide source (e.g., potassium cyanide or acetone cyanohydrin). The mixture is stirred in a reaction pot until the rearrangement is substantially complete at a temperature below 50° C., preferably about 20° C. to about 40° C., and the desired product is recovered by conventional techniques.

The term "cyanide source" refers to a substance or substances which under the rearrangement conditions consists of or generates hydrogen cyanide and/or cyanide anion.

The process is conducted in the presence of a catalytic amount of a source of cyanide anion and/or hydrogen cyanide, together with a molar excess, with respect to the enol ester, of a moderate base.

Preferred cyanide sources are alkali metal cyanides such as sodium and potassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4 carbon atoms in the alkyl groups, such as acetone or methyl isobutyl ketone cyanohydrins; cyanohydrins of benzaldehyde or of C₂ -C₅ aliphatic aldehydes such as acetaldehyde, propionaldehyde, etc., cyanohydrins; zinc cyanide; tri(lower alkyl) silyl cyanides, notably trimethyl silyl cyanide; and hydrogen cyanide itself. Hydrogen cyanide is considered most advantageous as it produces relatively rapid reaction and is inexpensive. Among cyanohydrins the preferred cyanide source is acetone cyanohydrin.

The cyanide source is used in an amount up to about 50 mole percent based on the enol ester. It may be used in as little as about 1 mole percent to produce an acceptable rate of reaction at about 40° C. on a small scale. Larger scale reactions give more reproducible results with slightly higher catalyst levels of about 2 mole percent. Generally about 1-10 mole % of the cyanide source is preferred.

The process is conducted with a molar excess, with respect to the enol ester, of a moderate base. By the term "moderate base" is meant a substance which acts as a base yet whose strength or activity as a base lies between that of strong bases such as hydroxides (which could cause hydrolysis of the enol ester) and that of weak bases such as bicarbonates (which would not function effectively). Moderate bases suitable for use in this embodiment include both organic bases, e.g., trialkylamines such as triethylamine and inorganic bases such as alkali metal carbonates and phosphates. Suitable inorganic bases include potassium carbonate and trisodium phosphate.

The base is used in an amount of from about 1 to about 4 moles per mole of enol ester, preferably about 2 moles per mole.

When the cyanide source is an alkali metal cyanide, particularly potassium cyanide, a phase transfer catalyst may be included in the reaction. Particularly suitable phase transfer catalysts are the crown ethers.

A number of different solvents are useful in this process, depending on the nature of the acid halide or the acylated product. A preferred solvent for this reaction is 1,2-dichloroethane. Other solvents which may be employed, depending on the reactants or products include toluene, acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, and methyl isobutyl ketone (MIBK).

In general, depending on the nature of the reactants and the cyanide source, the rearrangment may be conducted at temperatures up to about 50° C.

The above described substituted benzoyl chlorides can be prepared from the corresponding substituted benzoic acids according to the teaching of Reagents for Organic Synthesis, Vol. I, L. F. Fieser and M. Fieser, pp. 767-769 (1967). ##STR9## wherein R, R⁵ and R⁶ are as previously defined.

The substituted benzoic acids can be prepared by a wide variety of general methods according to the teaching of The Chemistry of Carboxylic Acids and Esters, S. Patai, editor, J. Wiley and Sons, New York, N.Y. (1969) and Survey of Organic Synthesis, C. A. Buehler and D. F. Pearson, J. Wiley and Sons, (1970).

The following are three representative examples of the methods described therein. ##STR10## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (a) the substituted benzonitrile is heated to reflux in aqueous sulfuric acid for several hours. The mixture is cooled and the reaction product is isolated by conventional techniques. ##STR11## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (b) the substituted acetophenone is heated to reflux for several hours in an aqueous hypochlorite solution. The mixture is cooled and the reaction product is isolated by conventional techniques. ##STR12## wherein R, R⁵ and R⁶ are as previously defined.

In reaction (c) the substituted toluene is heated to reflux in an aqueous solution of potassium permanganate for several hours. The solution is then filtered and the reaction product is isolated by conventional techniques.

The above-described 5-hydroxy-4,4,6,6-tetra-substituted 1,3-cyclohexanediones can be prepared according to reaction (d). ##STR13## wherein R¹ through R⁴ are as defined and R⁷ is hydrogen.

In reaction (d) NaBH₄ is added to a basic methanolic solution of the syncarpic acid under controlled conditions and reacted at room temperature. The reaction solution is acidified and the product recovered by conventional techniques.

When R⁷ is C₁ -C₄ alkyl, C₂ -C₅ alkenyl, C₂ -C₅ alkynyl or cyano, the dione can be prepared by reacting a nucleophile such as methyl lithium with a 4,4,6,6-tetra-substituted 1,3,5-cyclohexanetrione as displayed in reaction (e). ##STR14## wherein R¹ through R⁴ are as defined and R⁷ is C₁ -C₄ alkyl, C₂ -C₅ alkenyl, C₂ -C₅ alkynyl or cyano.

In reaction (e) the lithium compound is added to a solution of the syncarpic acid reactant under controlled conditions and reacted at room temperature. The reaction solution is then acidified and the product recovered by conventional techniques.

The following examples teach the synthesis of a representative compound of this invention.

EXAMPLE 1 5-Hydroxy-4,4,6,6-tetramethyl-1,3-cyclohexanedione ##STR15##

To a solution of the syncarpic acid [2.0 grams (g), 11.0 millimole (mmol)] in methanol [30 milliliters (ml)] at 0° C. was added a solution of NaOMe in MeOH (25%, 50 ml, 22.0 mmol). NaBH₄ (1.1 g, 29.0 mmol) was then added, the ice bath was removed, and the reaction mixture was allowed to stir at room temperature for 5 hours. The basic reaction was acidified with aqueous 1 normal hydrochloric acid (1N HCl) at 0° C. The organic product was extracted into diethyl ether. The combined ether extracts were dried (MgSO₄), filtered, and concentrated to a slight yellow solid (1.92 g, m.p. 180-184). The product was homogeneous as determined by thin layer chromatography. It was identified as such by nuclear magnetic resonance spectroscopy, infrared spectroscopy and mass spectroscopy.

EXAMPLE 2 2-(2'-Nitro-4'-trifluoromethylbenzoyl)-5-hydroxy-4,4,6,6-tetramethyl-1,3-cyclohexanedione ##STR16##

2-Nitro-4-trifluoromethylbenzoyl chloride (20.5 g, 81 mmol) and 5-hydroxy-4,4,6,6-tetramethyl-1,3-cyclohexanedioine (10.0 g, 54 mmol) were dissolved in methylene chloride. To this mixture was added triethylamine (23 ml, 162 mmol) and DMF (5 drops) and the resulting solution was allowed to stir at room temperature for 3 hours. The solution was washed with aqueous 1N HCl, followed by aqueous 5% K₂ CO₃. The organic layer was dried (MgSO₄), filtered and concentrated to a brown glassy solid (17.68 g) under vacuum. The solid was dissolved in acetonitrile (88 ml). Acetone cyanohydrin (2 ml, 22 mmol) and triethylamine (12.3 ml, 88 mmol) were added and the mixture stirred at room temperature for 3.5 hours. The solvent and excess triethylamine were removed under reduced pressure and the residue was dissolved in methylene chloride. The organic layer was washed with aqueous 1N HCl. The acidic materials were then extracted into aqueous 5% K₂ CO₃. The latter was then acidified at 0° C. with concentrated HCl until the pH was between 5 and 6. The desired triketone was then extracted into CH₂ Cl₂. The combined organic layers were dried (MgSO₄), filtered and concentrated under vacuum to a white solid (9.3 g, m.p. 136-140). The product was identified by nuclear magnetic resonance spectroscopy, infrared spectroscopy and mass spectroscopy.

The following is a table of certain selected compounds that are preparable according to the procedure described hereto. Compound numbers are assigned to each compound and are used throughout the remainder of the application.

                                      TABLE I                                      __________________________________________________________________________      ##STR17##                                                                     Comp.                                                                          No. R  R.sup.1                                                                           R.sup.2                                                                           R.sup.3                                                                           R.sup.4                                                                           R.sup.5                                                                            R.sup.6                                                                              R.sup.7                                                                           m.p. °C.                                __________________________________________________________________________     1   NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   H     H  158-161                                        .sup. 2.sup.a                                                                      NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-CF.sub.3                                                                           H  136-140                                        3   Cl CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-Cl  H  50-55                                          4   NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-Cl  H  95-97                                          5   Cl CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          3-Cl                                                                               4-SO.sub.2 Et                                                                        H  65-75                                          6   NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-SO.sub.2 CH.sub.3                                                                  H  65-75                                          7   Cl CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-SO.sub.2 CH.sub.3                                                                  H  75-85                                          8   NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          5-CH.sub.3                                                                         H     H  150-157                                        9   Cl CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          5-Br                                                                               H     H  140-145                                        10  NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-CF.sub.3                                                                           CH.sub.3                                                                          gummy oil                                      11  NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-Cl  CH.sub.3                                                                          110-116                                        12  NO.sub.2                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H   4-SO.sub.2 CH.sub.3                                                                  CH.sub.3                                                                          oil                                            __________________________________________________________________________      .sup.a Prepared in Example 2.                                            

Herbicidal Screening Tests

As previously mentioned, the herein described compounds produced in the above-described manner are phytotoxic compounds which are useful and valuable in controlling various plant species. Selected compounds of this invention were tested as herbicides in the following manner.

Pre-emergence herbicide test. On the day preceding treatment, seeds of seven different weed species are planted in loamy sand soil in individual rows using one species per row across the width of a flat. The seeds used are green foxtail (FT) (Setaria viridis), watergrass (WG) (Echinochloa crusgalli), wild oat (WO) (Avena fatua), annual morningglory (AMG) (Ipomoea lacunosa), velvetleaf (VL) (Abutilon theophrasti), Indian mustard (MD) (Brassica juncea), and yellow nutsedge (YNG) (Cyperus esculentus). Ample seeds are planted to give about 20 to 40 seedlings per row, after emergence, depending upon the size of the plants.

Using an analytical balance, 600 milligrams (mg) of the compound to be tested are weighed out on a piece of glassine weighing paper. The paper and compound are placed in a 60 milliliter (ml) wide-mouth clear bottle and dissolved in 45 ml of acetone or substituted solvent. Eighteen ml of this solution are transferred to a 60 ml wide-mouth clear bottle and diluted with 22 ml of a water and acetone mixture (19:1) containing enough polyoxyethylene sorbitan monolaurate emulsifier to give a final solution of 0.5% (v/v). The solution is then sprayed on a seeded flat on a linear spray table calibrated to deliver 80 gallons per acre (748 L/ha). The application rate is 4 lb/acre (4.48 Kg/ha).

After treatment, the flats are placed in the greenhouse at a temperature of 70° to 80° F. and watered by sprinkling. Two weeks after treatment, the degree of injury or control is determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% is recorded for each species as percent control with 0% representing no injury and 100% representing complete control.

The results of the tests are shown in the following Table II.

                  TABLE II                                                         ______________________________________                                         Pre-Emergence Herbicidal Activity                                              Application Rate - 4.48 kg/ha                                                  Cmpd.                                                                          No.    FT      WG     WO   AMG   VL   MD    YNG                                ______________________________________                                         1      100     100    100  90    100  100   80                                 2      100     100    100  100   100  100   80                                 8      100     100    100  100   100  100   80                                 9      100     100    100  100   100  100   80                                 10     100     100    100  95    100  100   80                                 11     100     100    100  90    100  100   80                                 12     100     100    100  90    100  100   80                                 ______________________________________                                    

Post-Emergence Herbicide Test: This test is conducted in an identical manner to the testing procedure for the pre-emergence herbicide test, except the seeds of the seven different weed species are planted 10-12 days before treatment. Also, watering of the treated flats is confined to the soil surface and not to the foliage of the sprouted plants.

The results of the post-emergence herbicide test are reported in Table III.

                  TABLE III                                                        ______________________________________                                         Post-Emergence Herbicidal Activity                                             Application Rate - 4.48 kg/ha                                                  Cmpd.                                                                          No.    FT      WG     WO   AMG   VL   MD    YNG                                ______________________________________                                         1      100     100    100  85    100  100   80                                 2      100     100    95   90    100  100   90                                 8      100     100    90   90     90   80   90                                 9      100     100    100  100   100  100   80                                 10     100      95    90   90    100  100   80                                 11      90      90    85   90    100  100   80                                 12      95      90    80   100   100  100   80                                 ______________________________________                                    

Pre-Emergence Multi-Weed Herbicide Test

Several compounds were evaluated at an application rate of 0.25 lb/acre (0.28 kg/ha) for pre-emergence activity against a larger number of weed species.

The process was generally similar to the pre-emergence herbicide test described above except that only 37.5 milligrams of test compound were weighed out and the application rate was 40 gallons per acre.

Redroot pigweed (PW) was eliminated in this test and the following weed species were added:

    ______________________________________                                         Grasses:                                                                              downybrome    Bromus tectorum                                                                              (DB)                                               annual ryegrass                                                                              Lolium multiflorum                                                                           (ARG)                                              rox-orange sorghum                                                                           Sorghum bicolor                                                                              (SHC)                                              hemp sesbanis Sesbania exaltata                                                                            (SESB)                                             nightshade    Solanum sp.   (SP)                                               cocklebur     Xanthium sp.  (CB)                                        ______________________________________                                    

The results of the 0.28 kg/ha test are shown in Table IV.

                                      TABLE IV                                     __________________________________________________________________________     Pre-Emergence Multi-Weed Herbicide Test                                        Application Rate - 0.28 kg/ha                                                  Cmpd.                                                                          No. DB FT ARG WG SHC WO BSG AMG SESB                                                                               VL SP YNS CB                               __________________________________________________________________________     1   -- 100                                                                               95  100                                                                               100 90 100  0   30  85                                                                               40 100  0                               2   -- 100                                                                               100 100                                                                               100 100                                                                               100 90  100 100                                                                               95 100 --                               3   -- 100                                                                               100 100                                                                               100 100                                                                               100 100  95  95                                                                               20 100 75                               4   -- 100                                                                               100 100                                                                               100 100                                                                               40  35  100 100                                                                               98 100 75                               5   -- 100                                                                               60  100                                                                                80 15 15  100 100 100                                                                                0  40 100                              6   -- 100                                                                               20  100                                                                               100 15 15  85  100 100                                                                               95 100 100                              7   -- 100                                                                               70  100                                                                                95 25 10  95  100 100                                                                               60  95 90                               __________________________________________________________________________      A dash (--) indicates not tested.                                        

Post-Emergence Multi-Weed Herbicide Test

Several compounds were evaluated at an application rate of 0.25 lb/acre (0.28 kg/ha) for post-emergence activity against the larger number of weed species that were used in the pre-emergence multi-weed herbicide test.

The process was generally similar to the post-emergence herbicide test described above except that only 37.5 milligrams of test compound were weighed out and the application rate was 40 gallons per acre.

The results of the 0.28 kg/ha test are shown in Table V.

                                      TABLE V                                      __________________________________________________________________________     Post-Emergence Multi-Weed Herbicide Test                                       Application Rate - 0.28 kg/ha                                                  Cmpd.                                                                          No. DB FT ARG WG SHC WO BSG AMG SESB                                                                               VL SP YNS CB                               __________________________________________________________________________     1   -- 100                                                                               95  100                                                                               100 100                                                                               --  50  85  60 30 100 --                               2   -- 100                                                                               100 100                                                                               100 100                                                                               --  90  100 100                                                                               100                                                                               --  100                              3   -- 90 20  90 70  100                                                                               100 98  95  95 50 75  100                              4   -- 95 70  90 75  75 85  75  90  80 75 50  75                               5   -- 35 50  95 25  35  0  50  75  60  0 15  75                               6   -- 75 10  95 35  35 10  50  90  50 25 20  75                               7   -- 90 35  95 40  40 10  70  90  50 25 80  80                               __________________________________________________________________________      A dash (--) indicates not tested.                                        

The compounds of the present invention and their salts are useful as herbicides and can be applied in a variety of ways at various concentrations. In practice, the compounds or salts are formulated into herbicidal compositions, by admixture, in herbicidally effective amounts, with the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural applications, recognizing the fact that the formulation and mode of application of a toxicant may affect the activity of the materials in a given application. Thus, these active herbicidal compounds or salts can be formulated as granules of relatively large particle size, as wettable powders, as emulsifiable concentrates, as powdery dusts, as flowables, as solutions or as any of several other known types of formulations, depending upon the desired mode of application. These formulations may contain as little as about 0.5% to as much as about 95% or more by weight of active ingredient. A herbicidally effective amount depends upon the nature of the seeds or plants to be controlled and the rate of application varies from about 0.01 to approximately 10 pounds per acre, preferably from about 0.02 to about 4 pounds per acre.

Wettable powders are in the form of finely divided particles which disperse readily in water or other dispersants. The wettable powder is ultimately applied to the soil either as a dry dust or as a dispersion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas and other readily wet organic or inorganic diluents. Wettable powders normally are prepared to contain about 5% to about 95% of the active ingredient and usually also contain a small amount of wetting, dispersing, or emulsifying agent to facilitate wetting and dispersion.

Emulsifiable concentrates are homogeneous liquid compositions which are dispersible in water or other dispersant, and may consist entirely of the active compound or salt with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthal, isophorone and other non-volatile organic solvents. For herbicidal application, these concentrates are dispersed in water or other liquid carrier and normally applied as a spray to the area to be treated. The percentage by weight of the essential active ingredient may vary according to the manner in which the composition is to be applied, but in general comprises about 0.5% to 95% of active ingredient by weight of the herbicidal composition.

Granular formulations wherein the toxicant is carried on relatively coarse particles, are usually applied without dilution to the area in which suppression of vegetation is desired. Typical carriers for granular formulations include sand, fuller's earth, attapulgite clay, bentonite clays, montmorillonite clay, vermiculite, perlite and other organic or inorganic materials which absorb or which may be coated with the toxicant. Granular formulations normally are prepared to contain about 5% to about 25% of active ingredients which may include surface-active agents such heavy aromatic naphthas, kerosene or other petroleum fractions, or vegetable oils; and/or stickers such as destrins, glue or synthetic resins.

Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their salts; polyhydric alcohols; polyethoxylated alcohols; esters and fatty amines; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used, normally comprises from 0.1% to 15% by weight of the herbicidal composition.

Dusts, which are free-flowing admixtures of the active ingredient with finely divided solids such as talc, clays, flours and other organic and inorganic solids which act as dispersants and carriers for the toxicant, are useful formulations for soil-incorporating application.

Pastes, which are homogeneous suspensions of a finely divided solid toxicant in a liquid carrier such as water or oil, are employed for specific purposes. These formulations normally contain about 5% to about 95% of active ingredient by weight, and may also contain small amounts of a wetting, dispersing or emulsifying agent to facilitate dispersion. For application, the pastes are normally diluted and applied as a spray to the area to be affected.

Other useful formulations for herbicidal applications include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene and other organic solvents. Pressurized sprays, typically aerosols, wherein the active ingredient is dispersed in finely-divided form as a result of vaporization of a low boiling dispersant solvent carrier, such as the Freons, may also be used.

The phytotoxic compositions of this invention can be applied to the plants in the conventional manner. Thus, the dust and liquid compositions can be applied to the plant by the use of power-dusters, boom and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or a spray or by rope wick applications because they are effective in very low dosages. In order to modify or control growth of germinating seeds or emerging seedlings, as a typical example, the dust and liquid compositions can be applied to the soil according to conventional methods and can be distributed in the soil to a depth of at least 1/2 inch below the soil surface. It is not necessary that the phytotoxic compositions be mechanically admixed with the soil particles since these compositions can also be applied merely by spraying or sprinkling the surface of the soil. The phytotoxic compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein. Dust compositions, granular compositions or liquid formulations applied to the surface of the soil can be distributed below the surface of the soil by conventional means such as discing, dragging or mixing operations. In the following examples the herbicidal compound can be substituted with the herbicidal salt of the compound.

    __________________________________________________________________________     EMULSIFIABLE CONCENTRATE FORMULATIONS                                          General Formula with Ranges                                                                         Specific Formula                                          Herbicidal compound                                                                           5-55  herbicidal compound                                                                         24                                           surfactant(s)  5-25  proprietary blend of oil-                                                                   10                                           solvent(s)     20-90 soluble sulfonates and                                                   100%  polyoxyethylene ethers                                                         polar solvent                                                                               27                                                                petroleum hydrocarbon                                                                       39                                                                             100%                                         WETTABLE POWDER FORMULATIONS                                                   herbicidal compound                                                                            3-90 herbicidal compound                                                                         80                                           wetting agent  0.5-2 sodium dialkyl naphthalene                                                                  0.5                                          dispersing agent                                                                              1-8   sulfonate                                                 diluent(s)     8.5-87                                                                               sodium lignosulfonate                                                                       7                                                           100%  attapulgite clay                                                                            12.5                                                                           100%                                         EXTRUDED GRANULAR FORMULATIONS                                                 herbicidal compound                                                                           1-20  herbicidal compound                                                                         10                                           binding agent  0-10  lignin sulfonate                                                                            5                                            diluent(s)     70-99 calcium carbonate                                                                           85                                                          100%               100%                                         FLOWABLE FORMULATIONS                                                          herbicidal compound                                                                           20-70 herbicidal compound                                                                         45                                           surfactant(s)  1-10  polyoxyethylene ether                                                                       5                                            suspending agent(s)                                                                           0.05-1                                                                               attagel      0.05                                         antifreeze agent                                                                              1-10  propylene glycol                                                                            10                                           antimicrobial agent                                                                           1-10  1,2-benzisothiazoline-3-one                                                                 0.03                                         antifoam agent 0.1-1 silicone defoamer                                                                           0.02                                         solvent        7.95-77.85                                                                           water        39.9                                                        100%               100%                                         __________________________________________________________________________

When salts are used as the active ingredient in the herbicidal compositions of this invention it is recommended to use salts that are agriculturally acceptable.

The phytotoxic compositions of this invention can also contain other additives, for example, fertilizers, other herbicides and other pesticides, used as adjuvant or in combination with any of the above-described adjuvants. Fertilizers useful in combination with the active ingredients include, for example, ammonium nitrate, urea and superphosphate. 

What is claim is:
 1. Compounds of the formula ##STR18## wherein R is hydrogen; halogen; C₁ -C₂ alkyl; C₁ -C₂ alkoxy; nitro; cyano; C₁ -C₂ haloalkyl; or R^(a) SO_(n) -- wherein n is 0 or 2 and R^(a) is C₁ -C₂ alkyl, trifluoromethyl or difluoromethyl; or trifluoromethoxy or difluoromethoxy;R¹ is hydrogen or C₁ -C₄ alkyl; R² is hydrogen or C₁ -C₄ alkyl; or R¹ and R² together are C₂ -C₅ alkylene; R³ is C₁ -C₄ alkyl; R⁴ is C₁ -C₄ alkyl; or R³ and R⁴ together are C₂ -C₅ alkylene; R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) --SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; and (13) --N(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and R⁷ is hydrogen, C₁ -C₄ alkyl, C₂ -C₅ alkenyl, C₂ -C₅ alkynyl or cyano and their salts.
 2. The compounds of claim 1 wherein R is chlorine, hydrogen, bromine, methyl, methoxy, nitro, trifluoromethyl or methylsulfonyl; R¹, R², R³ and R⁴ are methyl; R⁵ and R⁶ independently are (1) hydrogen; (2) halogen; (3) C₁ -C₄ alkyl; (4) C₁ -C₄ alkoxy; (5) trifluoromethoxy; (6) cyano; (7) nitro; (8) C₁ -C₄ haloalkyl; (9) R^(b) SO_(n) -- wherein n is the integer 0, 1 or 2; and R^(b) is (a) C₁ -C₄ alkyl; (b) C₁ -C₄ alkyl substituted with halogen or cyano; (c) phenyl; or (d) benzyl; (10) --NR^(c) R^(d) wherein R^(c) and R^(d) independently are hydrogen or C₁ -C₄ alkyl; (11) R^(e) C(O)-- wherein R^(e) is C₁ -C₄ alkyl or C₁ -C₄ alkoxy; or (12) SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined; or (13) --N--(R^(c))C(O)R^(d) wherein R^(c) and R^(d) are as defined; and R⁷ is hydrogen.
 3. The compounds of claim 2 wherein R⁵ and R⁶ are independently hydrogen; chlorine; fluorine; bromine; methyl; C₁ -C₄ alkoxy; trifluoromethoxy; cyano; nitro; trifluoromethyl; R^(b) SO_(n) -- wherein n is the integer 0 or 2 and R^(b) is methyl, chloromethyl, trifluoromethyl; ethyl or n-propyl, R^(e) C(O)-- where R^(e) is C₁ -C₄ alkyl; or SO₂ NR^(c) R^(d) wherein R^(c) and R^(d) are as defined and R⁵ is in the 3-position or 5-position; R⁶ is in the 4-position; and R⁷ is hydrogen.
 4. The compounds of claim 2 wherein R⁵ is hydrogen and R⁶ is hydrogen, chlorine, bromine, fluorine, cyano, trifluoromethyl or R^(b) SO₂ wherein R^(b) is C₁ -C₄ alkyl or C₁ -C₄ haloalkyl.
 5. The compound of claim 2 wherein R is nitro, R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is hydrogen; and R⁷ is hydrogen.
 6. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-chlorine; and R⁷ is hydrogen.
 7. The compound of claim 2 wherein R is chlorine; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-chlorine; and R⁷ is hydrogen.
 8. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-trifluoromethyl; and R⁷ is hydrogen.
 9. The compound of claim 2 wherein R is chlorine; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is 3-chlorine; R⁶ is 4-SO₂ C₂ H₅ ; and R⁷ is hydrogen.
 10. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-SO₂ CH₃ ; and R⁷ is hydrogen.
 11. The compound of claim 2 wherein R is chlorine; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-SO₂ CH₃ ; and R⁷ is hydrogen.
 12. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is 5-methyl; R⁶ is hydrogen; and R⁷ is hydrogen.
 13. The compound of claim 2 wherein R is chlorine; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is 5-bromine; R⁶ is hydrogen; and R⁷ is hydrogen.
 14. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-trifluoromethyl; and R⁷ is methyl.
 15. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl, R⁵ is hydrogen; R⁶ is 4-chlorine; and R⁷ is methyl.
 16. The compound of claim 2 wherein R is nitro; R¹ is methyl; R² is methyl; R³ is methyl; R⁴ is methyl; R⁵ is hydrogen; R⁶ is 4-SO₂ CH₃ ; and R⁷ is methyl. 